Nearly half the nation has tighter voting restrictions today than four years ago.

Since the 2010 election, 22 states have passed new voting requirements, according to the nonprofit law and policy institute the Brennan Center for Justice at New York University, which advocates against many of the restrictions. In 15 of those states, this year marks the first major federal election with those new policies in place. Seven states are facing court challenges over their tighter voting laws.

The restrictions have a disproportionate impact on the black population, according to a review of census data. While the 22 states are home to 46 percent of the overall population, they represent 57 percent of the nation’s black population. The Hispanic population, however, is underrepresented: just 42 percent live in the states with new voting requirements. The restrictions range from photo ID requirements to narrower windows for early voting.

Most were passed by GOP-led legislatures in states with growing minority turnout, the report finds. In 18 of the 22 states, the restrictions were ushered through GOP-led bodies. The requirements will also have an outsized effect on states with high minority turnout. Seven of the states with new requirements are among the 11 with the highest African American turnout in 2008. Nine of the states with new restrictions are among the 12 with the highest Hispanic turnout.

Proponents of such policies say they boost election integrity and reduce voter fraud. Opponents argue that they discourage turnout. Academic studies have found that voter fraud is incredibly rare and are mixed on the impact such policies have on turnout.

The Brennan Center report characterizes the recent passage of voter requirements as a marked shift. Between early 2011 and the 2012 election, state lawmakers introduced at least 180 restrictive voting bills in 41 states, with such policies passing in 19 states by the 2012 election. Laws requiring that voters present some form of ID at the polls are in effect in 31 states, according to a count last month by the bipartisan National Conference on State Legislatures.

The report breaks the new requirements into four broad categories: tighter identification laws introduced in 13 states; greater registration requirements introduced in 10 states; narrower early voting windows in 8 states; and restricting the voting rights of those with past convictions in 3 states. (Some states passed multiple new requirements.)

The 7 states facing court challenges

(Brennan Center)

The seven states facing challenges over their new voting requirements are Arizona, Arkansas, Kansas, North Carolina, Ohio, Texas and Wisconsin, as shown in the map above. (Iowa is shaded a different color because, while there is a lawsuit there, it targets an administrative action and not a law.)

The 16 states that passed expansions to voter access since 2012

Expansions will be in effect this fall for the darker-shaded states. (Brennan Center)

Of the 16 states that have passed expansions to voting access in the past two years, 11 modernized their registration systems, making it easier for eligible citizens to sign up. Early voting was expanded in three states, while youths in their late teens were granted the ability to pre-register to vote in another three. Oklahoma weakened its photo ID law. Colorado expanded ballot access to non-English speakers, while Mississippi and Oklahoma expanded absentee ballot access.